Estimation of Metabolizable Energy Requirement for Pregnant Sows by the Factorial Method

Abstract

National Institute of Animal Industry, Tsukuba Norin Kenkyu Danchi, Ibaraki-ken 305 In order to determine metabolizable energy (ME) requirement for pregnant sows by the factorial method, respiration trials and nitrogen (N) balance trials were conducted for 2 days at 89±3 days of pregnancy using 16 pregnant sows. 2.0kg and 2.5kg diets, differing mainly in ME content, were given to pregnant sows. Fat retention in the body was estimated using energy and protein retention data for the whole body. Two different model equations were used for estimating the ME requirement for pregnant sows. The results are summarized as follows:
(1) In the case of the linear regression model, ME intake (ME, kcal/W^0.75kg/day) was related to energy retention in the whole body (ER, kcal/W^0.75kg/day) via the following equation: ME=81.0+1.17 ER. From this equation, the ME requirement for maintanance (MEm) and ME efficiency for energy retention were estimated at 81 kcal/W^0.75kg/day and 85.5%, respectively.
(2) In the case of the multiple regression model, the relationship between energy retention (kcal/W^0.75kg/day) as protein (P) and fat (F) accretion in the whole body, and ME intake (kcal/W^0.75kg/day), was expressed as follows: ME=81.2+1.15P+1.16F. From this equation, MEm and ME efficiencies for protein and fat accretion were estimated at 81kcal/W^0.75/day and 87.0 and 86.2%, respectively. Since the partial regression coefficient (1.15) of P in the above equation was not significant, the 87% efficiency value was considered unreliable.
(3) Using the results of the present study and a previous paper and the data collected from literature, the ME requirements for pregnant sows of 120, 140 and 160kg body weight at mating were calculated by assuming 20, 30 and 40kg of net weight gain (excluding uterus and its contents) during pregnancy. This value was compared with that of ARC which was estimated using a model equation differing from those in the present study. The difference between ME requirements estimated using the two model equations in the present study was small (within a range of 2 to 4%). The difference between ME requirements in the present study and those in ARC was relatively small (within a range of about -4 to 9%).